Leflunomide And Diclofenac Sodium Gel

INDICATION AND USAGE For the treatment of adults with active rheumatoid arthritis (RA). For the temporary relief of arthritis pain.

DOSAGE AND ADMINISTRATION SEE PRESCRIBING DIRECTIONS FOR EACH COMPONENT CONTAINED IN THIS KIT Take one leflunimide 20 mg once daily. The maximum recommended daily dosage is 20 mg once per day. Apply 2-4 grams of diclofenac 1% gel to treated area as needed up to 4 times per day. Do not usea on more than 2 body areas at the same time.

6 ADVERSE REACTIONS The following serious adverse reactions are described elsewhere in the labeling: Hepatotoxicity [see Warnings and Precautions (5.2)] Immunosuppression [see Warnings and Precautions (5.4)] Bone marrow suppression [see Warnings and Precautions (5.4)] Stevens-Johnson syndrome and toxic epidermal necrolysis [see Warnings and Precautions (5.5)] Peripheral neuropathy [see Warnings and Precautions (5.7 )] Interstitial lung disease [see Warnings and Precautions (5.8)] The most commonly reported adverse reactions (≥10%) regardless of relation to leflunomide tablets treatment were diarrhea, respiratory infection, nausea, headache, rash, abnormal liver enzymes, dyspepsia. (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Lupin Pharmaceutical Inc. at 1-800-399-2561 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch 6.1 Clinical Trials Experience Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice. In clinical studies (Trials 1, 2, and 3), 1,865 patients were treated with leflunomide tablets administered as either monotherapy or in combination with methotrexate or sulfasalazine. Patients ranged in age from 19 to 85 years, with an overall median age of 58 years. The mean duration of RA was 6 years ranging from 0 to 45 years. Elevation of Liver Enzymes Treatment with leflunomide tablets was associated with elevations of liver enzymes, primarily ALT and AST, in a significant number of patients; these effects were generally reversible. Most transaminase elevations were mild (≤ 2-fold ULN) and usually resolved while continuing treatment. Marked elevations (>3-fold ULN) occurred infrequently and reversed with dose reduction or discontinuation of treatment. Table 1 shows liver enzyme elevations seen with monthly monitoring in clinical trials Trial 1 and Trial 2. It was notable that the absence of folate use in Trial 3 was associated with a considerably greater incidence of liver enzyme elevation on methotrexate. In a 6 month study of 263 patients with persistent active rheumatoid arthritis despite methotrexate therapy, and with normal LFTs, leflunomide tablets was administered to a group of 130 patients starting at 10 mg per day and increased to 20 mg as needed. An increase in ALT greater than or equal to three times the ULN was observed in 3.8% of patients compared to 0.8% in 133 patients continued on methotrexate with placebo. Most Common Adverse Reactions The most common adverse reactions in leflunomide tablets -treated patients with RA include diarrhea, elevated liver enzymes (ALT and AST), alopecia and rash. Table 2 displays the most common adverse reactions in the controlled studies in patients with RA at one year (≥ 5% in any leflunomide tablets treatment group). Adverse events during a second year of treatment with leflunomide tablets in clinical trials were consistent with those observed during the first year of treatment and occurred at a similar or lower incidence. Less Common Adverse Reactions In addition, in controlled clinical trials, the following adverse events in the leflunomide tablets treatment group occurred at a higher incidence than in the placebo group. These adverse events were deemed possibly related to the study drug. Blood and Lymphatic System: leukocytosis, thrombocytopenia; Cardiovascular: chest pain, palpitation, thrombophlebitis of the leg, varicose vein; Eye: blurred vision, eye disorder, papilledema, retinal disorder, retinal hemorrhage; Gastrointestinal: alkaline phosphatase increased, anorexia, bilirubinemia, flatulence, gamma-GT increased, salivary gland enlarged, sore throat, vomiting, dry mouth; General Disorders: malaise; Immune System: anaphylactic reaction; Infection: abscess, flu syndrome, vaginal moniliasis; Nervous System: dizziness, headache, somnolence; Respiratory System: dyspnea;

12.3 Pharmacokinetics Following oral administration, leflunomide is metabolized to an active metabolite, teriflunomide, which is responsible for essentially all of leflunomide's in vivo activity. Plasma concentrations of the parent drug, leflunomide, have been occasionally seen at very low concentrations. Studies of the pharmacokinetics of leflunomide have primarily examined the plasma concentrations of the active metabolite, teriflunomide. Absorption Following oral administration, peak teriflunomide concentrations occurred between 6 to 12 hours after dosing. Due to the very long half-life of teriflunomide (18 to 19 days), a loading dose of 100 mg for 3 days was used in clinical studies to facilitate the rapid attainment of steady-state teriflunomide concentrations. Without a loading dose, it is estimated that attainment of steady- state plasma concentrations would require about two months of dosing. The resulting plasma concentrations following both loading doses and continued clinical dosing indicate that plasma teriflunomide concentrations are dose proportional. Effect of Food Co-administration of leflunomide tablets with a high fat meal did not have a significant impact on teriflunomide plasma concentrations. Distribution Teriflunomide is extensively bound to plasma protein (>99%) and is mainly distributed in plasma. The volume of distribution is 11 L after a single intravenous (IV) administration. Elimination Teriflunomide, the active metabolite of leflunomide, has a median half-life of 18 to 19 days in healthy volunteers. The elimination of teriflunomide can be accelerated by administration of cholestyramine or activated charcoal. Without use of an accelerated drug elimination procedure, it may take up to 2 years to reach plasma teriflunomide concentrations of less than 0.02 mg/L, due to individual variation in drug clearance [see Warnings and Precautions ( 5.3 )]. After a single IV administration of the metabolite (teriflunomide), the total body clearance of teriflunomide was 30.5 mL/h. Metabolism In vitro inhibition studies in human liver microsomes suggest that cytochrome P450 (CYP) 1A2, 2C19 and 3A4 are involved in leflunomide metabolism. In vivo , leflunomide is metabolized to one primary (teriflunomide) and many minor metabolites. In vitro , teriflunomide is not metabolized by CYP450 or flavin monoamine oxidase enzymes. The parent compound is rarely detectable in plasma. Excretion Teriflunomide, the active metabolite of leflunomide, is eliminated by direct biliary excretion of unchanged drug as well as renal excretion of metabolites. Over 21 days, 60.1% of the administered dose is excreted via feces (37.5%) and urine (22.6%). After an accelerated elimination procedure with cholestyramine, an additional 23.1% was recovered (mostly in feces). Studies with both hemodialysis and CAPD (chronic ambulatory peritoneal dialysis) indicate that teriflunomide is not dialyzable. Specific Populations Gender. Gender has not been shown to cause a consistent change in the in vivo pharmacokinetics of teriflunomide. Smoking. A population based pharmacokinetic analysis of the clinical trial data indicates that smokers have a 38% increase in clearance over non-smokers; however, no difference in clinical efficacy was seen between smokers and nonsmokers. Drug Interaction Studies Drug interaction studies have been conducted with both leflunomide and with its active metabolite, teriflunomide, where the metabolite was directly administered to the test subjects. The Potential Effect of Other Drugs on Leflunomide tablets Potent CYP and transporter inducers: Following concomitant administration of a single dose of leflunomide tablets to subjects receiving multiple doses of rifampin, teriflunomide peak concentrations were increased (~40%) over those seen when leflunomide tablets was given alone [see Drug Interactions ( 7 )]. An in vivo interaction study with leflunomide tablets and cimetidine (non-specific weak CYP inhibitor) has demonstrated a lack of a significant impact on teriflunomide exposure. The Potential Effect of leflunomide tablets on Other Drugs CYP2C8 Substrates There was an increase in mean repaglinide C max and AUC (1.7-and 2.4-fold, respectively), following repeated doses of teriflunomide and a single dose of 0.25 mg repaglinide, suggesting that teriflunomide is an inhibitor of CYP2C8 in vivo. The magnitude of interaction could be higher at the recommended repaglinide dose [see Drug Interactions ( 7 )]. CYP1A2 Substrates Repeated doses of teriflunomide decreased mean C max and AUC of caffeine by 18% and 55%, respectively, suggesting that teriflunomide may be a weak inducer of CYP1A2 in vivo. OAT3 Substrates There was an increase in mean cefaclor C max and AUC (1.43-and 1.54-fold, respectively), following repeated doses of teriflunomide, suggesting that teriflunomide is an inhibitor of organic anion transporter 3 (OAT3) in vivo [see Drug Interactions ( 7 )] BCRP and OATP1B1/1B3 Substrates There was an increase in mean rosuvastatin C max and AUC (2.65-and 2.51-fold, respectively), following repeated doses of teriflunomide, suggesting that teriflunomide is an inhibitor of BCRP transporter and organic anion transporting polypeptide 1B1 and 1B3 (OATP1B1/1B3) [see Drug Interactions ( 7 )]. Oral Contraceptives There was an increase in mean ethinylestradiol C max and AUC 0 to 24 (1.58-and 1.54-fold, respectively) and levonorgestrel C max and AUC 0 to 24 (1.33-and 1.41-fold, respectively) following repeated doses of teriflunomide [see Drug Interactions ( 7 )]. Teriflunomide did not affect the pharmacokinetics of bupropion (a CYP2B6 substrate), midazolam (a CYP3A4 substrate), S-warfarin (a CYP2C9 substrate), omeprazole (a CYP2C19 substrate), and metoprolol (a CYP2D6 substrate).